It's very fast to do, probably 15-20 mins if you know waht to do; however, polycount is not very low. The more details you have the bigger polycount. For games, I think you need to retopo, if you consider this way of modeling.

I have done something to game models and I feel that poly modeling is the way to go there; also, careful UV mapping is a must with low poly models.

For low poly game modeling Blender is very good; Wings3D and Milkshape 3D are good options too. Curvy is more of an artistic tool.

However, I also saw how easy it was to use Curvy for making some cool creations when playing with the demo. So I figured it is probably a great tool for the process of experimentation and generating ideas for a "what to make". Even if I have to then use another tool to make a final product, or refine some basic building blocks from a Curvy creation, I think it will help my workflow.

This is probably even more "true" to a non-artist like myself, as trying to actually make something start to finish in some of the other products was a pretty daunting task when I originally looked into it.

Some of the things listed in this gallery here have given me some cool ideas already. I will definitely look at those products you listed as well, especially for helping out final creation of entities and such for game development.

I like using Curvy to make models that I render out as sprites for 2D games, and backgrounds too.
Here's my last one a cartoony sci-fi game.

"Lo-poly" for games seems to include tens of thousands of triangles, compared to "hi-poly" multi-million triangle models. A lot of people seem to create a complex model first, then swap it into other software to make a simpler shell to use in-game, either by re-topology or by simply building up a new mesh around the hipoly.